GENUS MAGOSPH^RA. 323 



GENUS I. MAGOSPH^RA, Haeckel. 



Animalcules free-swimming, united in social clusters, joined to each 

 other centrally by an inward extension of their prolonged posterior 

 extremities, the anterior or exposed margin of each animalcule clothed 

 with long vibratile flagella ; endoplast and contractile vesicle conspicuous, 

 increasing by the subdivision into sporular elements of a single encysted 

 zooid. Inhabiting salt water. 



Professor Haeckel * has proposed to create a special and independent class of 

 his sub-kingdom of the Protista, which he denominates the Catallacta, for the 

 reception of the as yet single known type bearing the above generic title, dis- 

 covered by himself on the coast of Norway. It is evident, however, that the 

 structure, life history, and developmental features of this organism, as reported by 

 himself, accord so closely with those of all the ordinary representatives of the 

 Infusoria Flagellata, as recorded in this volume, that any such complete isolation of 

 this particular type is altogether artificial and uncalled for. Individually examined, 

 the zooids of Magosphara correspond remarkably with those of the endoparasitic 

 type Lophomonas, last described, and if encountered separately under like con- 

 ditions would undoubtedly be relegated to the same multiflagellate genus. Their 

 coherence in spheroidal clusters, again, and maintenance of a free-swimming 

 existence, find precise parallels in such genera as Synura, Syncrypfa, and Uroglena, 

 while the ultimate assumption by the zooids of an amoeboid phase and subdivision 

 into sporular elements are common to the majority, if not to the entire section of the 

 Pantostomatous Flagellata. Mostly, among the ordinary Flagellata, the resultants of 

 such a process of multiple fission or sporular subdivision become scattered asunder 

 throughout the surrounding water ; a like more or less permanent coherence of the 

 subdivisional derivatives is nevertheless maintained by the three last-named genera, 

 and, with certain modifications, recurs in those motile reproductive products of the 

 sponges, the " swarm-gemmules " or so-called " ciliated larvae," discussed at length 

 in Chapter V., and which are there shown to consist similarly of ovate or sub- 

 spheroidal aggregations of flagellate animalcules. The only essential distinction 

 manifested by the several types just quoted consists of the fact that in these latter 

 the constituent zooids of the spheroidal or ovate masses are monoflagellate or 

 biflagellate, while in those of the present generic group they are polyflagellate. 

 While thus reluctantly compelled to ignore Professor Haeckel's claim on behalf of 

 Magosph&ra of a title carrying with it the comprehensive significance he would 

 attach to it, his denomination of the same, slightly modified so as to reduce its 

 import to that only of a family name, is here preserved. 



Magosphsera planula, Haeckel. PL. I. FIGS. 12-17. 



Bodies pyriform, forming spheroidal clusters, united to each other 

 centrally by an attenuate inward prolongation of their posterior 

 extremities, the interstices between being filled in by a common gela- 

 tinous matrix or zoocytium, the anterior margin truncate flattened, 

 the antero-lateral borders polyhedral through mutual pressure ; flagella 

 equalling one-half of the length of the body, developed from the entire 

 exposed anterior surface ; endoplast spherical, situated in the median line 

 towards the anterior extremity ; contractile vesicle single, subcentral. 

 Diameter of adult sphere-masses 1-320". 



HAB. Salt water, Norwegian coast. 



* " Die Catallacten, eine neue Protistengruppe," ' Jenaische Zeitschrift,' Bd. vi., 1870. 



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